WO2014068052A1

WO2014068052A1 - Cooling device for gases occurring in installation equipment

Info

Publication number: WO2014068052A1
Application number: PCT/EP2013/072802
Authority: WO
Inventors: Albert Zacharias; Christian Ruempler
Original assignee: Eaton Electrical Ip Gmbh & Co. Kg
Priority date: 2012-10-31
Filing date: 2013-10-31
Publication date: 2014-05-08
Also published as: DE102012110409A1; US9899158B2; EP2915173A1; EP2915173B1; CN104798161A; US20150279586A1; CN104798161B

Abstract

The invention relates to a cooling device 10 for hot gases occurring during and after a switching process in electrical installation equipment, preferably in low-voltage circuit breakers. According to the invention, a window 13 with narrow passage openings 17, 18 is arranged in the flow path 20 of the hot switching gases, and the window 13 is made from a material with high thermal conductivity and high heat capacity. The passage openings 17, 18 in the window are planar in shape and are arranged parallel to the flow direction 20 of the switching gases such that no deflection of the switching gases takes place.

Description

COOLING DEVICE FOR INSTALLATION DEVICES

GASES

The invention relates to a cooling device for during and after a switching operation in electrical installation equipment, preferably occurring in low-voltage circuit breakers hot gases.

When switching off electrical currents in electromechanical switchgear creates a switching arc when opening the contacts. The arc heats the air in the

Switching chamber on, which leads to an increase in pressure and consequently to a flow of the heated gases through exhaust openings - hereinafter called blowout. These heated and conductive gases also contain in finely divided form solid particles and depending on the composition and gas temperature even after leaving the

Installation device differently conductive. In the design of switching chambers

(Housing strength), the processes at the blow-out (temperature, chamber pressure) must be considered.

Much of the arc energy is already in the switching chamber through the

Chamber walls added. For cooling and distribution of the switching arc quenching plates are usually used in circuit breakers that cause the rapid extinguishment of the arc. This arc cooling in the switching chamber takes place at a high temperature level and takes place essentially by radiation transport.

The hot blown gases are electrically conductive and can outside the

Installation device Ignite arcs between live parts and cause damage unless sufficient safety distance to adjacent, conductive and possibly live parts is maintained.

It is a cooling device in low-voltage circuit breakers known in which a close-meshed metallic mesh or grid is used (EP 0817223 Bl). Other inventions deal with the cooling of the blow-out;

for example in US 7488915 B2 or in DE 102010034264 B3. In these solutions, however, the flow is deflected several times. Disadvantages of these arrangements are that a pressure build-up is created by the flow deflection along the cooling device, which adversely affects the switching behavior. If you want to avoid this reaction, a cross-sectional enlargement must be made. Through the complex

Flow guidance (inter alia, many deflections) and the filigree structure can occur in the close-meshed cooling braids (EP 0817223 AI) to blockages of the flow channels by particles in the blowout and damage to the braid.

DE 1640265 AI shows a cascade of cooling devices in which plates are angled at the outlet of a precooler, making a return path of arcs is difficult. Furthermore, DE 35 41 514 A1 shows an arc extinguishing chamber with an attachment for further cooling of the escaping gases.

The object of the invention is to provide a device to installation devices, which serves the cooling of blown switching gases, and in which there is only a minimal pressure build-up in the switching chamber. The solution of the problem can be found in the features of the main claim. Advantageous embodiments are formulated in subclaims.

An essential aspect of the invention is that with as low as possible

Influence the switching gases in the gas flow path a window with narrow

Pass through openings, and the window of a material higher

Thermal conductivity and high, by volume and mass specific heat capacity is present. The passage openings in the window are formed planar and arranged parallel to each other. The passage openings form the flow path and direction of the switching gases. With the cooling device, the temperature of the switching gases is lowered so far that this their electrical conductivity and thus a substantial part of their

Loss of damage. The switching behavior is little influenced. By the cooling device, neither the flow nor the pressure build-up in the switching chamber is significantly affected. The blow-out is performed between parallel flat cooling plates, for example made of materials (metal) with a very small distance (slot). The cooling plate spacing is significantly smaller than typical arc splitter spacing. The short distance ensures a good convective heat transfer from the gas into the surface of the cooling device. Due to the high thermal conductivity, the heat is dissipated quickly from the surface. Melting of the material is avoided. The heat is cached in the plates themselves, which is achieved by a corresponding heat capacity of the plates. Due to the arranged parallel to the flow and planar plates does not occur

Flow deflection on; the pressure build-up is reduced to a minimum. Of the

geometrically simple construction makes the arrangement according to the invention less sensitive to damage and blockages caused by the blow-out.

Metallic cooling plates of the cooling device may (need not) be conductively connected together. The cooling device should be in the flow path behind one

Arc extinguishing device may be arranged. The cooling device should be at the end of the

Switching chamber may be arranged such that an over the arc extinguishing device also exiting arc does not reach the cooling device. Such an arc must not find any contact, foot point on the cooling device. The cooling plates are made relatively thin and not suitable for an arc extinguishing device.

Narrow slots between the cooling plates ensure good heat transfer between gas and cooling plates. Advantageously, slots in the order of 0.1 to 0.5 mm wide. The dimensioning of the window, that is number of slots and width and width of the slots is based on the Ausblasverhalten of the specific device. The given one

Total cross section is determined by the number of slots, by the slot width and the

Slot width determined. The dimensioning of the cooling device is essentially determined by the switching behavior of the installation device, with the parameters switching capacity and rated current. Preferred embodiments are briefly enumerated below

• The openings are formed by flat cooling plates; the

Cold plates form a compact stack as a self-supporting structure.

• The entire flow of switching gas penetrates the passages. lateral

Openings should not be present; possibly close by appropriate sealing.

• All cooling plates have the same thickness, preferably a thickness of 500 to 1000 μιη may be provided, the thickness of large

Heat absorption capacity of the cooling plates smaller values and lower

Heat absorption capacity of the cooling plates assumes larger values.

• All openings should be made of flat cooling plates; all passages can have the same extent.

• The passages have a width of 100 to 500 μιη across the flow direction.

• The cooling device can be detachably mounted on the housing of an installation device or installed in the installation device.

In the choice of material for the cooling device, a material with good thermal conductivity paired with high heat capacity and sufficiently high melting temperature is selected. These properties are fulfilled according to the invention e.g. various steels (preferably simpler

Structural steel) and copper alloys. But even thermally conductive ceramics can be used in principle. The cooling plate thickness and the material of the cooling plates are chosen so that the heat of the outgassing is absorbed without melting.

The cooling plates may preferably be formed as a compact stack, which means that the cooling plates are mechanically connected to each other. With appropriate

Elements that are arranged on the side or between the cooling plates, a precise adherence to the small intermediate distances is ensured. In this compact form, the stack can be inserted into the window formed in the switching current path or into a frame formed there. The entire switching gas flow is to penetrate the stack. The stack is sealed against side openings.

The metallic plates of the cooling device can be electrically conductively connected. As already mentioned, an obstacle in the exhaust duct creates an increase in pressure, which is on the Reverse switching behavior of the installation device. In particular, ask

Flow deflections such an obstacle. The present arrangement should make do with minimal pressure increase. Installation devices are each designed so that the switching chamber against current, and dependent on the maximum switching capacity

Pressure increases remains intact.

Advantages of the invention

According to the invention, deflections are avoided in the gas guide, so that an increase in pressure is reduced to a minimum. This also allows the cooling device optionally (according to customer requirements) outside the device (the switching chamber) before the

To mount the blowout without causing any relevant repercussions on the switching behavior.

By avoiding deflections in the gas guide and the clogging of the assembly is reduced by deposits, in contrast, for example, to fine mesh metal mesh. Even partial blockage can lead to increased pressure build-up.

The inventive arrangement can in principle in all electromechanical

Switching devices that produce a significant blow-out, are used.

Advantageously, this may be the case with circuit breakers, circuit breakers and

Motor circuit breakers happen.

• The cooling process takes place with a simultaneous reduced pressure gradient.

• The cooling device can optionally be mounted on the installation device (for example as an accessory). The cooling device can also be introduced in a frame, which can then be attached to an installation device.

• A safety distance to other conductive parts located near the installation device can be reduced because the escaping switching gases are deionized and cooled so far that they are no longer conductive.

• Reduced shielding effort when using switchgear in tight enclosures, control cabinets, etc. The invention is illustrated in drawings, which show by way of example in detail:

1: cooling device in the switching gas flow of a switching device, and FIG. 2: cooling device in detail (sectional view)

FIG. 1 shows by way of example a cooling device 10 which is installed in the terminal cover (or in the blow-out channel) of an installation device shown as a circuit breaker. In the flow path 20, or in the outlet opening of the hot switching gases, a window 13 with narrow passage openings 17, 18 of a material of high thermal conductivity and high heat capacity is arranged. The cooling device is flowed through by the switching gas flow 20 from the switching chamber 11. Burning arcs should not be able to reach the cooling device. The attachment in the installation device may be such that the

Cooling device forms an integral part of the device, or the cooling device may be detachably attachable to the housing of the installation device. Appropriate

Fixing means not shown, but may for example consist of screw connections.

Figure 2 is a sectional view with the cooling device 10 cut perpendicularly in the middle (with reference numeral 12 as the cutting plane). Between the passage openings 17 are arranged transversely to the flow direction 20 cooling plates 15 and form the

Cooling plate stack. The location of the cooling plates 15 may be horizontal (as shown in FIG.) Or vertical. In the illustrated embodiment of FIG. 2 there are twenty-three cooling plates which, together with the frame 14, form the heat capacity of the cooling device in terms of mass, volume and material. Twenty-two slots 17 are formed between the cooling plates.

All cooling plates 15 have the same thickness 16. Preferably, the thickness 16 should have a size between 500 to 1000 μιη. For special applications, the thickness can be selected in a narrower range of 700 to 900 μιη.

All passage openings, which are formed as flat, planar-shaped slots 17, have the same extent with respect to width 18 and width 19. The slot width 18 transverse to the flow direction 20 and transversely to the orientation of the cooling plates can each according to Expected gas mass flow graded amount: 100 to 500 μιη, or 250 to 400 μιη, or even narrower 200 to 300 μιη. The total cross section of the passage openings is in

Essentially determined by and dependent on switching capacity or rated current of

Installation device. The overall cross-section of the passage openings of the design illustrated in FIG. 2 has an order of magnitude of 300 mm ² , if the width = 0.2 mm, the width = 20 mm and the number 22 is used.

reference numeral

10 cooling device

11 switching chamber

12 cutting plane

13 windows

14 frames

15 cooling plate

16 plate thickness

17 slot

18 slots wide

19 slot width

20 switching gas flow

Claims

claims

1. Cooling device for after a switching operation in electrical installation equipment, especially in low-voltage circuit breakers, occurring switching gases, wherein in the flow path of the switching gases a window (13) with narrow passage openings (17) is arranged, and the window (13, 19) of a metallic Material is formed with high thermal conductivity and / or high heat capacity, characterized in that in the window, the passage openings (17) from ebenfiächigen and parallel to the flow direction (20) of the switching gases aligned cooling plates (15) are formed.

2. Cooling device according to claim 1, characterized in that the cooling plates (15) form a compact stack in the form of a self-supporting structure.

3. Cooling device according to claim 1 or 2, characterized in that the cooling plates (15) consist of a steel or copper alloy.

4. Cooling device according to one of the preceding claims, characterized in that all the cooling plates (15) have the same thickness (16).

5. Cooling device according to claim 4, characterized in that the cooling plates (15) have a thickness (16) of 500 to 1000 μιη, preferably from 700 to 900 μιη.

6. Cooling device according to one of the preceding claims, characterized in that all passage openings (17) with respect to width (18) and width (19) have the same extent.

7. Cooling device according to claim 6, characterized in that the passage openings (17) transversely to the flow direction and transversely to the orientation of the cooling plates have a width (18) of 100 to 500 μιη.

8. Cooling device according to one of the preceding claims, characterized in that the cooling device (10) is detachably arranged on the housing of an installation device.

9. Cooling device according to one of claims 1 to 7, characterized in that the cooling device (10) is integrated in the housing of an installation device.

10. Cooling device according to one of the preceding claims, characterized in that the cooling device (10) in the flow path (20) behind a

Arc extinguishing device is arranged.